It may be desirable to construct absorptive devices, such as disposable diapers with fasteners, pull-on diapers, training pants, sanitary napkins, pantiliners, incontinence briefs, and the like, with stretch laminates to improve the ease of motion and maintenance of a sustained fit. Furthermore, stretch laminates allow the diaper to accommodate a range of different sized wearers. A diaper may have stretch laminates in a number of its article elements including the waist band, leg cuffs, side panels, elasticized topsheets, backsheet, ears, outercover, and fastening system.
As disclosed in U.S. Pat. No. 7,717,893 and U.S. Pub. No. US 2005-0273071, there is a need for an absorbent product comprising a stretch laminate that retracts slowly upon being released from a stretched state, thus facilitating application and positioning of the product correctly onto the wearer. U.S. Pat. No. 7,717,893 and U.S. Pub. No. US 2005-0273071 further disclose various embodiments of slow recovery polymers, films, and/or laminates for the purpose of meeting said need, as well as meeting various other needs and desires.
A problem that can exist in filling the need for a slow recovery stretch laminate is that the manufacture and packaging of an absorbent article comprising a slow recovery stretch laminate may result in the slow recovery stretch laminate being held under strain while the absorbent article is stored within its distribution package. That is, the slow recovery stretch laminate may not be in its fully relaxed state during storage. This strain lock can lead to a loss in performance as the product ages, for example, a drop in the unload force of the slow recovery stretch laminate at 37° C. which could result in poor fit. Depending on the placement of the slow recovery stretch laminate(s) within an absorbent article and on the particular absorbent article, poor fit can lead to, for example, increased urine or bowel movement leakage during use, sagging or drooping of the absorbent article during use, or increased discomfort in wearing the absorbent article. The level to which the unload force is reduced can depend on the level of strain lock (aging strain), the aging time, and the thermal history of the slow recovery stretch laminate during aging.
Another problem that can exist in filling the need for a slow recovery stretch laminate is that during the use of an absorbent article comprising a slow recovery stretch laminate comprising an elastic member, certain baby oils, lotions, gels, cremes, and the like, that are spread on the wearer's skin before application of the article, may be absorbed to some extent by the elastic member. This absorption may lead to a swelling or breakage of the elastic member and may result in reduced performance. Swelling may lead to (1) a sticky feeling slow recovery stretch laminate that may cause discomfort to the wearer of the absorbent article, and/or (2) a reduction in the unload force of the slow recovery stretch laminate at 37° C., which may result in poor fit and may lead to, for example, increased urine or bowel movement leakage during use, sagging or drooping of the absorbent article during use, and/or increased discomfort in wearing the absorbent article. Breakage of the elastic member may lead to poor fit if it is localized, but if widespread may lead to catastrophic failure of the slow recovery stretch laminate which may lead to the failure of the absorbent article comprising the slow recovery stretch laminate. The degree to which absorption may occur may depend on the particular construction of the slow recovery stretch laminate, for example, on the type and basis weight of the substrate and on the type and basis weight of any adhesive used to join the elastic member to the substrate, as well as where it is located within the absorbent article. For example, the use of a slow recovery stretch laminate as a waist feature or side panel is in an area of an absorbent article that is less likely to encounter residual baby oil, lotions, gels, and the like, as compared to the use of the slow recovery stretch laminate as an elasticized topsheet. It is an object of the present disclosure to provide various embodiments that offer solutions to said problems, while still also meeting the needs and desires of using a slow recovery polymer, film, and/or laminate as disclosed in U.S. Pat. No. 7,717,893 and U.S. Pub. Nos. 2005-0273071, 2006-0155255, 2006-0167434, and 2009-0134049.
Further, it is an object of the present disclosure to provide various embodiments of slow recovery elastomers, films, and laminates comprising an hydrogenated block copolymer useful for overcoming the problems expressed in the previous paragraphs. Still further, it is an object of the present disclosure to provide various properties of slow recovery polymers, films, and laminates that in combination with an hydrogenated block copolymer are useful for overcoming the problems expressed in the previous paragraphs including (1) an order-disorder transition temperature of greater than about 135° C., (2) a hard phase glass transition temperature of greater than about 60° C., (3) a combination of one or more hard block associating ingredients that maintain or increase the glass transition temperature of at least one equivalent hard block polymer of the hydrogenated block copolymer, (4) a force retention factor of greater than about 2, (5) aromatic substitution of either or both the soft block and the hard block, and (6) certain combinations thereof. Additionally, it is an object of the present disclosure to provide various embodiments of slow recovery polymers, films, and laminates that in combination with a block copolymer are useful for overcoming the problems expressed in the previous paragraphs including (1) hard blocks with a solubility parameter of greater than about 9.1 (cal/cm3)1/2, and (2) compositions that remain extendable to at least 50% engineering strain after exposure to isopropyl palmitate for 30 hours at room temperature.